Semiclassical gravity effects near horizon formation

DOI: 
10.1088/1361-6382/ab2e43
Publication date: 
01/08/2019
Main author: 
Barceló, Carlos
IAA authors: 
Barceló, Carlos
Authors: 
Barceló, Carlos;Boyanov, Valentin;Carballo-Rubio, Raúl;Garay, Luis J.
Journal: 
Classical and Quantum Gravity
Refereed: 
Yes
Publication type: 
Article
Volume: 
36
Pages: 
165004
Abstract: 
We study the magnitude of semiclassical gravity effects near the formation of a black-hole horizon in spherically-symmetric spacetimes. As a probe for these effects we use a quantised massless scalar field. Specifically, we calculate two quantities derived from it: the renormalised stress─energy tensor (a measure of how the field vacuum state affects the spacetime) and the effective temperature function (a generalisation of Hawking temperature related to the energy flux of the field vacuum). The subject of our study are spacetimes which contain a spherical distribution of matter and an empty exterior Schwarzschild region, separated by a surface which is moving in proximity to the Schwarzschild radius , with M the total mass. In particular, we analyse the consequences of three types of surface movement: an oscillation just above , a monotonous approach towards in infinite time and a crossing of at different velocities. For a collapsing matter distribution which follows the expected dynamical evolution in general relativity, we recover the standard picture of black-hole formation and its tenuous semiclassical effects. In more general dynamical regimes, allowing deviations from the standard classical evolution, we obtain a variety of different effects: from the emission of Hawking-like radiation without the formation of a horizon, to large values of the renormalised stress─energy tensor, related to the Boulware vacuum divergence in static spacetimes.
Database: 
ADS
SCOPUS
URL: 
https://www.scopus.com/inward/record.uri?eid=2-s2.0-85072346578&doi=10.1088%2f1361-6382%2fab2e43&partnerID=40&md5=69f52f7b05836624b8b956c1bfdee3f6
ADS Bibcode: 
2019CQGra..36p5004B
Keywords: 
General Relativity and Quantum Cosmology;High Energy Physics - Theory